TANGO: Switch to DTG/3TC Non-Inferior to 3 Drug TAF-Containing Regimen

New data from the TANGO study demonstrate the non-inferior efficacy of dolutegravir/lamivudine (DTG/3TC) compared with a tenofovir alafenamide fumarate (TAF)-containing regimen of at least 3 drugs in virally suppressed individuals with HIV-1 infection.

“With HIV now considered a chronic condition and people living with HIV needing antiretroviral treatments for life, taking fewer medicines over a lifetime has become an important consideration for the community,” Kimberly Smith, MD, head of Global Research & Medical Strategy at ViiV Healthcare, said in a press release. “The TANGO study was designed to answer the question, can a 2-drug regimen of dolutegravir/lamivudine maintain viral suppression as well as a TAF-containing regimen?”

The full 48-week results of the phase 3, randomized, open-label, active-controlled, multicenter study were presented at the 10^th IAS Conference on HIV Science (IAS 2019).

The study enrolled 743 participants who were on a TAF-containing regimen with no history of virologic failure or resistance to nucleoside reverse transcriptase inhibitors or integrase inhibitors. The participants were randomized to switch to DTG/3TC or continue on the TAF-containing regimen through week 48.

The data presented at IAS 2019 indicate that the study met its primary end point for non-inferiority based on the proportion of participants with plasma HIV-1 RNA > 50 copies per mL at week 48.

The study found that switching to DTG/3TC was non-inferior to continuing a TAF-containing regimen (snapshot virologic failure: <1% vs <1%; adjusted difference: -0.3% [95% Confidence Interval =1.2, 0.7]).

Furthermore, it is reported that the proportion of patients with plasma HIV-1 RNA <50 c/mL was both high and similar in the treatment arms and demonstrated non-inferiority (93.2% [344 of 369] of participants in DTG/3TC compared with 93% [346 of 372] in the TAF-containing regimen arm).

At 48 weeks, 0 participants in the DTG/3TC group and 1 participant in the TAF-containing regimen group met confirmed virologic failure criteria; no resistance mutations were observed at failure.

Common adverse events (AEs) included nasopharyngitis, upper respiratory tract infections, and diarrhea. The percentage of participants who withdrew due to AEs was 4% in the DTG/3TC arm vs <1% in the TAF-containing regimen arm.

DTG/3TC was approved by the US Food and Drug Administration on April 8, 2019. The approval made DTG/3TC (Dovato) the first FDA-approved 2-drug, fixed-dose, complete regimen for treatment-naïve adults with HIV.

“These data present evidence that a dolutegravir/lamivudine 2-drug regimen is as effective as a TAF-containing, 3-drug regimen for people living with HIV,” Smith concluded.

The study, “Switching to DTG+3TC fixed dose combination (FDC) is non-inferior to continuing a TAF-based regimen (TBR) in maintaining virologic suppression through 24 weeks (TANGO Study),” was presented in a late-breaking oral abstract session on July 24, 2019, at IAS 2019 in Mexico City, Mexico.